Tantalum

Tantalum is atom number 73 — every Tantalum atom has exactly 73 protons in its center, and that number is what makes it Tantalum and nothing else. Its symbol is Ta. At room temperature it is a solid.

Tantalum is a chemical element with symbol Ta and atomic number 73. Previously known as tantalium, its name comes from Tantalus, an antihero from Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant.

Summary from the source dataset, derived from Wikipedia (CC BY-SA 3.0) · original article

Tantalum sits in period 6, group 5 of the d-block. Its 73 electrons fill shells of 2, 8, 18, 32, 11, 2 — written as [Xe] 4f14 5d3 6s2. Its electronegativity is 1.5 on the Pauling scale, and pulling the first electron off takes 761 kJ/mol. The outermost shell holds 2 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d3
Ionization energies (kJ/mol): 761, 1500
Electron affinity: 31 kJ/mol · Electronegativity (Pauling): 1.5
Density: 16.69 g/cm³ · melts 3290 K · boils 5731 K

Values exactly as published — see where the data comes from.